fentanyl

noun

fen·​ta·​nyl ˈfen-tə-ˌnil How to pronounce fentanyl (audio)
nonstandard -ˌnȯl
: a synthetic opioid narcotic analgesic C22H28N2O with pharmacological action similar to morphine that is administered transdermally as a skin patch and in the form of its citrate C22H28N2O·C6H8O7 is administered orally or parenterally (as by intravenous or epidural injection)

Examples of fentanyl in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The mailings come just three weeks before Election Day and are reminiscent of a similar threat in 2023, when several election offices received envelopes containing the powerful opioid fentanyl. — ABC News, 15 Oct. 2026 Some of those letters contained threats and traces of the powerful opioid fentanyl, leading some election offices to stock up on the overdose reversal medication naloxone. — Lisa Mascaro, Los Angeles Times, 15 Oct. 2026 Laura Carlisle, born two years ago already addicted to fentanyl, was the youngest person in the city chambers Tuesday. — Jennah Pendleton, Sacbee.com, 14 Oct. 2026 Following a global crackdown on fentanyl, a class of cheap, potent synthetics called nitazenes gained a foothold in the illicit drug market starting in 2019. — Mary Jane Gibson, Rolling Stone, 13 Oct. 2026 See All Example Sentences for fentanyl

Word History

Etymology

probably alteration of phenethyl, a monovalent radical derived from ethylbenzine, from phen- + ethyl

First Known Use

1964, in the meaning defined above

Time Traveler
The first known use of fentanyl was in 1964

Rhymes for fentanyl

See All Rhymes for fentanyl

Browse Nearby Words

fent
fentanyl
fenthion
See all Nearby Words

Cite this Entry

“Fentanyl.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fentanyl. Accessed 20 Oct. 2026.

Copy Citation

Medical Definition

fentanyl

noun
fen·​ta·​nyl ˈfent-ᵊn-ˌil How to pronounce fentanyl (audio)
: a synthetic opioid narcotic analgesic C22H28N2O with pharmacological action similar to morphine that is administered transdermally as a skin patch and in the form of its citrate C22H28N2O·C6H8O7 is administered orally or parenterally

Note: Fentanyl is marketed under the trademark Actiq.

More from Merriam-Webster on fentanyl

Britannica.com: Encyclopedia article about fentanyl

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of compunction

See Definitions and Examples »

Popular in Grammar & Usage

See More

'Affect' vs. 'Effect'

Merriam-Webster’s Great Big List of Words You Love to Hate

The Exceptions of '-s' and '-es' Plurals

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?
See More

Popular in Wordplay

See More

16 Food Words Recently Added to the Dictionary

The Real Origin of 'Supercalifragilistic'

9 Words That Sound Like Insults But Aren't

7 Words for Bad Endings and Rough Situations

Did 'orange' the fruit or the color come first?
See More

Popular

See More

'Affect' vs. 'Effect'

16 Food Words Recently Added to the Dictionary

The Real Origin of 'Supercalifragilistic'
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
artwork of illustrated limes with the text limes and smile with an arrow connecting the two words
Quiz: Spot the Anagram! Scramble these words to find new words with the e...
See All